are you double sure there isnt a split in any of the boost control hoses, wastegate actuator to amal, and amal to compressor housing

because for some reason the actuator isnt seeing the boost from the compressor housing, or if it is the gate isnt opening

the next step would be to run a pipe from wastegate actuator to compressor housing, this will bypass the amal valve and see if that stops it

if not ping the arm off the wastegate and make sure its free to move